Introduction: Automatic Alcohol Dispenser for Hands Without Arduino or Microcontrollers

About: Hello, my name is Carlos. I have a YouTube channel where I share my projects in

Video Tutorial

Step 1: Start

In this tutorial we will see how to create an automatic alcohol dispenser with water, to disinfect your hands. It is activated by approaching the hand to the reflective infrared sensor tcrt5000l, whose signal is amplified by an operational amplifier ua741cp. The output of this integrated is connected to the base of the pnp tip42c transistor, which is in charge of controlling a direct current motor. The motor together with other objects printed in 3d, create an electric pump, which is capable of supplying the alcohol to our hands with a hose that can be taken from a macro dropper, which are used in medicine.

Step 2: Electronic Diagram

Step 3: PCB

Step 4: TCRT500L


The TCRT5000 and TCRT5000L are reflective sensors, which include an infrared emitter and a phototransistor in a lead package that blocks visible light. Package Includes two mounting clips. TCRT5000L is the long lead version.


• Package type: leaded

• Detector type: phototransistor

• Dimensions (L x W x H in mm): 10.2 x 5.8 x 7

• Maximum operating distance: 2.5 mm

• Operating range within> 20% of relative collectorCurrent: 0.2mm to 15mm

• Typical Output Current Under Test: IC = 1mA

• Daylight Blocking Filter

• Emitter Wavelength: 950nm

• Lead Free Solder (Pb) Released

• Complies with 2002 RoHS Directive / 95 / EC and inaccordance with WEEE 2002/96 / CEAPPLICATIONS

• Position sensor for axis encoder

• Detection of reflective material such as paper, IBM cards,magnetic tapes, etc.

• Limit switch for mechanical movements in VCR

• General purpose: where space is limited

Step 5: TIP42C

Transistor polarity: PNP


Total Device Dissipation (Pc): 65 W

Collector-base voltage (Vcb): 140 V

Collector-Emitter Voltage (Vce): 100 V

Emitter-base voltage (Veb): 5 V

Maximum DC collector current (Ic): 6 A

Maximum operating temperature (Tj): 150 ° C

ELECTRICAL CHARACTERISTICS Current product - gain - bandwidth (ft): 3 MHz

Continuous current gain (hfe): 20

Packaging / Case: TO220

Step 6: UA741CP


• Short circuit protection

• Zero compensation voltage capacity

• Large common and differential mode voltage Ranks

• No frequency compensation required

• No lock Applications

• DVD Recorders and Players

• Professional Audio Mixers


The µA741 is a general-purpose operating device.amplifier with zero capacity of compensated voltage.The high common mode input voltage range and theabsence of lockout makes the amplifier ideal forvoltage follower applications. The device isshort circuit protected and the internal frequencycompensation ensures stability without externalcomponents.

Step 7: DIODE 1N4007

Step 8: RESISTOR 10K

Step 9: RESISTOR 150 OHM

Step 10: RESISTOR 220 OHM

Step 11: ENGINE






To put together this start-up project we can put it together on an experimental plate like the one published above, or on a breadboard.

This is good, for the experimentation stage, but once we have everything assembled and working correctly, we must take the next step.

Step 17: Gerber File

Subsequently, the final circuit was designed, and the necessary gerber files were generated to order the printed circuit

Download this gerber file from here ->

Step 18: 3D FILES

If you have a 3D printer, you can download the STL files, to print the pump and the bottle if you want to assemble, this hand sanitizer, or you can buy a submersible water pump, very cheap on any internet site and use any plastic container that have unoccupied at home.

Download STL file here ->

Step 19: The End